<!DOCTYPE html>
<html>
<head>
	<title>null</title>
</head>
<body>
	<h2>null的类型是对象</h2>
	<h2>null可以清空对象</h2>
	<p id="demo"></p>
	<script>
		var person = {
			"name": "aaa",
			"age": 18
		};
		person = null;
		document.getElementById("demo").innerHTML = typeof person;
	</script>

</body>
</html>